Which programs are you trying to install? Freeze ups in Windows usually have to do with improper video graphic drivers. Are you certain that you have installed all the necessary drivers for Windows XP?
If you go to Control Panel, System, Hardware Devices, and open the hardware tree, are all the drivers OK? In other words, are there any hardware items that have an exclamation mark over them ( ! ) ?
Don't remove Windows or use the Boot Camp assistant to recover the hard drive space yet. Let's see if we can figure out what's wrong first.